Finding the best way to use antibiotics before spinal surgery to help prevent antibiotic resistance

ISRCTN	ISRCTN75650267
DOI	https://doi.org/10.1186/ISRCTN75650267
Latvian Council of Science	lzp-2024/1-0303
Sponsor	Riga Stradiņš University
Funder	Latvijas Zinātnes Padome

Submission date: 07/09/2026
Registration date: 24/09/2026
Last edited: 24/09/2026

Recruitment status: Recruiting
Overall study status: Ongoing
Condition category: Infections and Infestations

Prospectively registered

Protocol

Statistical analysis plan

Results

Individual participant data

Record updated in last year

Plain English summary of protocol

Not provided at time of registration

Contact information

Prof Sigita Kazune
Principal investigator, Scientific, Public

Rīgas Stradiņa universitāte
Dzirciema iela 16
Riga
LV1007
Latvia

ORCID ID	0000-0002-7010-3238
Phone	+37126539996
Email	sigita.kazune@rsu.lv

Study information

Primary study design	Observational
Observational study design	Cohort study
Scientific title	Optimization of prophylactic antibacterial therapy in spinal surgery through mechanical PKPD modelling to reduce the emergence of antibiotic-resistant bacteria
Study acronym	OPATS-PKPD
Study objectives	1. To determine the concentration of preoperatively administered antibiotics in the patient's plasma and excised intervertebral disc tissue at the time of surgery. 2. To compare the concentration of antibiotics in serum and disc tissue with the degree of disc degenerative changes (Pfirrmann classification) and the status of endplates (Modic classification). 3. To evaluate the relationship between tissue antibiotic concentration and the incidence of postoperative spondylodiscitis. 4. To describe the demographic and clinical characteristics of the study population (sex, age, body weight, height, comorbidities, smoking status) in relation to the tissue pharmacokinetics of the antibiotics.
Ethics approval(s)	Approved 12/06/2026, Institutional Ethics Committee, Hospital of Traumatology and Orthopaedics, Riga, Latvia (Duntes iela 22, Riga, LV1005, Latvia; +37167 399 300; petijumi@tos.lv), ref: 21/2026/1
Health condition(s) or problem(s) studied	Perioperative antibacterial prophylaxis in spine surgery
Methodology	Patients will receive standard preoperative antibacterial prophylaxis (cefazolin or vancomycin) according to Hospital of Traumatology and Orthopaedics guidelines. Blood samples (5 mL) taken before prophylaxis and at prespecified time intervals (5, 15, 30, 60, 90 and 120 minutes relative to the dose) will be centrifuged (10 min at 3500 rpm). A portion (50-100 mg) of the intervertebral disc nucleus pulposus excised during the operation will be sampled. Serum and disc tissue will be frozen at -30°C and analyzed at the Riga Department of Pharmaceutical Chemistry. Antibiotic concentrations will be quantified with ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry. Patient demographics (weight, height, sex, comorbidities, smoking) and disc and endplate degeneration (Pfirrmann, Modic classification) will be analyzed. Patients will be evaluated for postoperative spondylodiscitis during hospitalization and at 2- and 4-month follow-ups.
Intervention type	Other
Primary outcome measure(s)	The concentration of preoperatively administered antibiotics in the patient's plasma and excised intervertebral disc tissue at the time of surgery measured using ultra-high performance liquid chromatography coupled with high-resolution mass spectrometry at 5, 15, 30, 60, 90 and 120 minutes (plasma) relative to the dose, and at the time of sampling (intervertebral disc tissue)
Key secondary outcome measure(s)	The relationship between intervertebral disc (IVD) antibiotic concentrations and the severity of disc degeneration (Pfirrmann classification) as well as endplate changes (Modic classification) measured using preoperative Magnetic Resonance imaging (MRI) quantification, at preoperative MRI and IVD concentration at disc sampling The incidence of postoperative spondylodiscitis measured using data collected during hospitalization and at 2- and 4-month follow-up visits with the surgeon at the end of the study The preoperative association between demographic/clinical variables (age, sex, BMI, comorbidities, smoking status) and IVD antibiotic penetration, measured using data collectd from patient case notes at the end of the study
Completion date	01/01/2028

Eligibility

Participant type(s)
Age group	Mixed
Lower age limit	18 Years
Upper age limit	100 Years
Sex	All
Target sample size at registration	200
Key inclusion criteria	1. Patients scheduled for cervical or lumbar discectomy and/or spinal fusion with an intervertebral disc implant 2. The patient will receive preoperative antibacterial prophylaxis 3. The patient has signed an informed consent form for participation in the study 4. Age 18 years and older
Key exclusion criteria	1. Glomerular filtration rate <30 mL/min/1.73 m² 2. Known allergy to beta-lactam antibiotics 3. Antibacterial therapy within the last month prior to surgery 4. Patient refusal to participate in the study
Date of first enrolment	01/10/2026
Date of final enrolment	01/12/2027

Locations

Countries of recruitment

Latvia

Study participating centres

Results and Publications

Individual participant data (IPD) Intention to share	No

Study outputs

Output type	Details	Date created	Date added	Peer reviewed?	Patient-facing?
Protocol file	in Latvian version 1.3	20/04/2026	09/09/2026	No	No

Additional files

50237_Protocol_v1.3_20April2026.pdf: in Latvian

Editorial Notes

14/09/2026: Study’s existence confirmed by the Latvian Council of Science (Latvijas Zinātnes Padome).